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<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<body>
  <script>
    // 数字类型
    const age = 20;
    const num = Infinity;
    const x = 1 / 0; // 1/0.000000000001
    const y = 'hello' - 2;
    console.log(x); // Infinity
    console.log(y); // NaN  not a number

    // 
  </script>
</body>

</html>